/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.db.metadata.idtable;

import org.apache.iotdb.commons.exception.MetadataException;
import org.apache.iotdb.commons.file.SystemFileFactory;
import org.apache.iotdb.commons.path.PartialPath;
import org.apache.iotdb.db.conf.IoTDBDescriptor;
import org.apache.iotdb.db.exception.metadata.PathNotExistException;
import org.apache.iotdb.tsfile.utils.FilePathUtils;
import org.apache.iotdb.tsfile.write.schema.IMeasurementSchema;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;

/**
 * This class manages one id table for each logical database
 */
public class IDTableManager {

    /**
     * logger
     */
    Logger logger = LoggerFactory.getLogger(IDTableManager.class);

    /**
     * database path -> id table
     */
    HashMap<String, IDTable> idTableMap;

    /**
     * system dir
     */
    private final String systemDir =
            FilePathUtils.regularizePath(IoTDBDescriptor.getInstance().getConfig().getSystemDir())
                    + "databases";

    // region IDManager Singleton
    private static class IDManagerHolder {

        private IDManagerHolder() {
            // allowed to do nothing
        }

        private static final IDTableManager INSTANCE = new IDTableManager();
    }

    /**
     * get instance
     *
     * @return instance of the factory
     */
    public static IDTableManager getInstance() {
        return IDManagerHolder.INSTANCE;
    }

    private IDTableManager() {
        idTableMap = new HashMap<>();
    }
    // endregion

    /**
     * get id table by device path
     *
     * @param devicePath device path
     * @return id table belongs to path's database
     */
    public synchronized IDTable getIDTable(PartialPath devicePath) {
        //    try {
        //      return idTableMap.computeIfAbsent(
        //
        // LocalSchemaProcessor.getInstance().getStorageGroupNodeByPath(devicePath).getFullPath(),
        //          storageGroupPath ->
        //              new IDTableHashmapImpl(
        //                  SystemFileFactory.INSTANCE.getFile(
        //                      systemDir + File.separator + storageGroupPath)));
        //    } catch (MetadataException e) {
        //      logger.error("get id table failed, path is: " + devicePath + ". caused by: " + e);
        //    }
        //
        //    return null;
        throw new UnsupportedOperationException();
    }

    /**
     * get id table by database path
     *
     * @param sgPath database path
     * @return id table belongs to path's database
     */
    public synchronized IDTable getIDTableDirectly(String sgPath) {
        return idTableMap.computeIfAbsent(
                sgPath,
                storageGroupPath ->
                        new IDTableHashmapImpl(
                                SystemFileFactory.INSTANCE.getFile(systemDir + File.separator + storageGroupPath)));
    }

    /**
     * get schema from device and measurements
     *
     * @param deviceName      device name of the time series
     * @param measurementName measurement name of the time series
     * @return schema entry of the time series
     */
    public synchronized IMeasurementSchema getSeriesSchema(String deviceName, String measurementName)
            throws MetadataException {
        for (IDTable idTable : idTableMap.values()) {
            IMeasurementSchema measurementSchema = idTable.getSeriesSchema(deviceName, measurementName);
            if (measurementSchema != null) {
                return measurementSchema;
            }
        }

        throw new PathNotExistException(new PartialPath(deviceName, measurementName).toString());
    }

    /**
     * clear id table map
     */
    public void clear() throws IOException {
        for (IDTable idTable : idTableMap.values()) {
            idTable.clear();
        }

        idTableMap.clear();
    }
}
